1. Field of the Invention
The present invention relates to optical imaging and, more particularly, to a system and method for automatic exposure calibration and compensation for degradation over time.
2. Description of the Related Art
The appropriate exposure value plays an important role in the acquisition of optical images, particular, when those images are to be further processed for machine vision and barcode decoding. For example, machine vision based systems are used for test tube and container identification and processing in sample handling systems as well as for barcode identification. Whether the exposure value is set correct has strong relationship with the robustness and accuracy of any machine vision algorithms. Setting and maintaining the optimal exposure is complicated, however, due to the different characteristics of cameras components, such as imaging sensor sensitivity, LED strength, and surroundings, such as external lighting, and reflective nature of background material and due to the fact that these characteristics can change over time. Accordingly, there is a need for a way to automatically calibrate exposure value and compensate for changes in the relevant characteristics over time.